There will always be a stigma attached to being non-academic in some circles, and academic in others too I would think. I feel a little like the voice of doom on this thread, but it really is unrealistic to think otherwise.
I don't actually see that so much has changed in the last 20 years actually UQD. There were mature students on my degree course then, and a mature PhD students when I was a postgrad too. My brother went back to college and re-took his A levels to get better grades in order to get to university having made a bit of a balls up first time round.
And I think perhaps one of the reasons why the failing the 11+ and being on the scrapheap thing seems less realistic is because there are fewer grammar school places, even in areas where there are grammar schools, so there is a reasonably, if not completely, comprehensive alternative for children who don't get in. More grammar school places would change that.
I do wonder how much flexibility there could be in a system where children follow academic or non-academic curricula in different buildings, even if they are on the same site. Perhaps it could work, but I need more convincing.